The present invention relates generally to a dedicated temperature management system for an electric storage battery particularly one for of an electric vehicle.
A hybrid electric vehicle combines a conventional usually fossil fuel-powered engine with some form of electric propulsion. The battery electric vehicle (BEV) is a type of electric vehicle that uses chemical energy stored in rechargeable battery packs. As with other electric vehicles, BEVs use electric motors and motor controllers, instead of internal combustions engines, for propulsion.
Battery electric cars are becoming more attractive due to higher oil prices and the advancement of new battery technologies that provide higher power, energy density, improved acceleration and greater range with fewer cells.
Batteries are among the most expensive component of BEVs. Rechargeable batteries used in electric vehicles include lead-acid, NiCd, nickel metal hydride, lithium ion, and Li-ion polymer. Optimum performance of advanced high energy density batteries requires that the battery temperature be maintained in an optimal range, whether the vehicle is operating, charging or standing idle, and regardless of the thermal loads caused by ambient conditions such as air temperature.
An analysis of vehicle battery thermal loads indicates that the battery thermal management system capacity requirements is strongly influenced by the ambient soak conditions the vehicle must accommodate rather than the actual battery charge and discharge operational losses.
Battery insulation for cold and hot conditions, cabin solar shading and cabin solar powered ventilation reduce substantially the active heating load and cooling load. A dedicated battery active/passive thermal system can be used to control the ambient thermal loads of the battery. I Isolation of the battery pack by thermal insulation, and reduce the in-cabin soak temperatures during high solar, high temperature conditions can reduce the thermal loads on the battery thermal system and significantly reduce the system size, cost and reduce the energy require to thermally mange the battery.
A system that controls temperature of advanced high energy batteries would use the cabin air conditioning system for active cooling, a separate coolant circuit for passive cooling, and an electric heater for battery heating.